First, the press release is copyrighted from its inception and may have been work for hire (a close call since you wrote them for an LLC and the LLC had a deal with them). There is a copyright in someone, although the absence of a copyright notice limits the remedies available for infringement.
Second, a link is not a copyright violation.
Third, copyright protects an exact manifestation of an idea or description of a fact, not the idea or fact itself.
Fourth, there are two different doctrines that could protect an exact copy of a press release.
One of two doctrines, which applies if the press release has been released to the public, is an implied license. Press releases are meant for the general public and reprinting them when that is their intended purpose is an implied grant of permission. In the same way, if you have an unfenced front yard to a concrete path leading to your front door, anyone who wishes to meet with you has an implied license to walk up to your door and knock. Whether this implied license can be revoked or not is a harder question.
The other of the two doctrines, which is not limited to press releases that have been released, is “fair use”. In this situation, when the work was short, has been released to others, has limited literary value, transmits unprotected facts relevant to you, relates facts that may also be a matter of public record (the sale anyway), and you aren’t trying to profit from the text of the press releases themselves just from the facts that they convey, the case for fair use is pretty decent even though this is a business use.
Ultimately, however, to be squeaky clean and avoid litigation, you can link rather than regurgitate the press releases, and can write your own statements about the facts in them from scratch.
This information is not privileged or trademarked.
If you didn’t sign a non-disclosure agreement (NDA) or if they were released to the public, they aren’t subject to trade secret protection either. If they were only released to the customer whose sale was involved and there is an NDA they could conceivably be trade secrets but even then the case would be very weak since the information doesn’t create value by virtue of being kept secret.